<?php
/**
 * User: Eric-Nothing
 * Datetime: 2019/6/24-14:19
 */

namespace App\Controllers;


class VolumeCalculator extends AreaCalculator
{
    public function __construct(array $shapes)
    {
        parent::__construct($shapes);
    }

    public function sum()
    {
        //该处遵循里氏替换原则,可以直接替换父类
        return 1;
    }

}